The Phalynx is slowly being replaced by RIM-116 RAM launchers which have amassed a sterling record of intercepts of incoming, high speed ASMs. New carriers are toating 2 RAM launchers (21 missiles each), 2 Sea Sparrow launchers (8 missiles each), and still 3 phalynx.
I'm sure they work great when working, as did the MK15.
But what is the % on operation?
A weapon system is only good when it can be deployed.
Seawolf was used effectively against aircraft and Exocets during the Falklands War and during Desert Storm successfully intercepted a Chinese-made Silkworm (Styx) that had been launched against a BB.
In view of its track record, I've often thought our big ships ought to carry it, but the Nav has relied on Sea Sparrow and Phalanx instead.